1
NEET 2025
MCQ (Single Correct Answer)
+4
-1
Change Language

Energy and radius of first Bohr orbit of $\mathrm{He}^{+}$and $\mathrm{Li}^{2+}$ are [Given $\mathrm{R}_{\mathrm{H}}=2.18 \times 10^{-18} \mathrm{~J}, \mathrm{a}_0=52.9 \mathrm{pm}$ ]

A
$$\begin{aligned} & \mathrm{E}_{\mathrm{n}}\left(\mathrm{Li}^{2+}\right)=-19.62 \times 10^{-16} \mathrm{~J} ; \\ & \mathrm{r}_{\mathrm{n}}\left(\mathrm{Li}^{2+}\right)=17.6 \mathrm{pm} \\ & \mathrm{E}_{\mathrm{n}}\left(\mathrm{He}^{+}\right)=-8.72 \times 10^{-16} \mathrm{~J} ; \\ & \mathrm{r}_{\mathrm{n}}\left(\mathrm{He}^{+}\right)=26.4 \mathrm{pm} \end{aligned}$$
B
$$\begin{aligned} & \mathrm{E}_{\mathrm{n}}\left(\mathrm{Li}^{2+}\right)=-8.72 \times 10^{-16} \mathrm{~J} ; \\ & \mathrm{r}_{\mathrm{n}}\left(\mathrm{Li}^{2+}\right)=17.6 \mathrm{pm} \\ & \mathrm{E}_{\mathrm{n}}\left(\mathrm{He}^{+}\right)=-19.62 \times 10^{-16} \mathrm{~J} ; \\ & \mathrm{r}_{\mathrm{n}}\left(\mathrm{He}^{+}\right)=17.6 \mathrm{pm} \end{aligned}$$
C
$$\begin{aligned} & \mathrm{E}_{\mathrm{n}}\left(\mathrm{Li}^{2+}\right)=-19.62 \times 10^{-18} \mathrm{~J} ; \\ & \mathrm{r}_{\mathrm{n}}\left(\mathrm{Li}^{2+}\right)=17.6 \mathrm{pm} \\ & \mathrm{E}_{\mathrm{n}}\left(\mathrm{He}^{+}\right)=-8.72 \times 10^{-18} \mathrm{~J} ; \\ & \mathrm{r}_{\mathrm{n}}\left(\mathrm{He}^{+}\right)=26.4 \mathrm{pm} \end{aligned}$$
D
$$\begin{aligned} & \mathrm{E}_{\mathrm{n}}\left(\mathrm{Li}^{2+}\right)=-8.72 \times 10^{-18} \mathrm{~J} ; \\ & \mathrm{r}_{\mathrm{n}}\left(\mathrm{Li}^{2+}\right)=26.4 \mathrm{pm} \\ & \mathrm{E}_{\mathrm{n}}\left(\mathrm{He}^{+}\right)=-19.62 \times 10^{-18} \mathrm{~J} ; \\ & \mathrm{r}_{\mathrm{n}}\left(\mathrm{He}^{+}\right)=17.6 \mathrm{pm} \end{aligned}$$
2
NEET 2025
MCQ (Single Correct Answer)
+4
-1
Change Language

Among the given compounds I-III, the correct order of bond dissociation energy of C-H bond marked with * is :

NEET 2025 Chemistry - Some Basic Concepts of Organic Chemistry Question 2 English

A
III $>$ II $>$ I
B
II $>$ III $>$ I
C
II $>$ I $>$ III
D
I $>$ II $>$ III
3
NEET 2025
MCQ (Single Correct Answer)
+4
-1
Change Language

Dalton's Atomic theory could not explain which of the following?

A
Law of multiple proportion
B
Law of gaseous volume
C
Law of conservation of mass
D
Law of constant proportion
4
NEET 2025
MCQ (Single Correct Answer)
+4
-1
Change Language

Identify the correct orders against the property mentioned

A. $\mathrm{H}_2 \mathrm{O}>\mathrm{NH}_3>\mathrm{CHCl}_3$-dipole moment

B. $\mathrm{XeF}_4>\mathrm{XeO}_3>\mathrm{XeF}_2$ - number of lone pairs on central atom

C. $\mathrm{O}-\mathrm{H}>\mathrm{C}-\mathrm{H}>\mathrm{N}-\mathrm{O}-$ bond length

D. $\mathrm{N}_2>\mathrm{O}_2>\mathrm{H}_2-$ bond enthalpy

Choose the correct answer from the options given below:

A
A, C only
B
B, C only
C
A, D only
D
B, D only
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